• Korean journal of food and cookery science
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• v.32 no.4
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• pp.383-389
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• 2016

Purpose: This study was conducted to evaluate the effect of rehydration and subsequent heating at high temperature on the pigments and antioxidants of dried samnamul (Aruncus dioicus) and daraesoon (Actinidia arguta). Methods: Rehydration included 16 h-soaking in cold water, and 30 min-boiling and 1 h-infusion in water. Rehydrated samnamul and daraesoon were heated at $180^{\circ}C$ for 10 or 20 min with or without perilla oil addition (10%) for cooking. Pigments and antioxidants were determined by HPLC and spectrophotometry. Results: Rehydration caused decreases in pigment and polyphenol contents, but increase in tocopherol content. Cooking by heating without addition of perilla oil resulted in increases in chlorophyll and carotenoid contents, but decreases in polyphenol and tocopherol contents. Decrease in tocopherol content by heating at $180^{\circ}C$ was reversed by the addition of perilla oil. Conclusion: This study strongly suggested that cooking of samnamul and daraesoon at $180^{\circ}C$ with perilla oil could improve color, texture, and potential health functionality by recovering the loss of antioxidants and pigments with antioxidant activity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.932-940
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• 2000

An experimental study on evaporative heat transfer characteristics in micro-fin tubes before and after expansion process has been performed with R-22. Single-grooved micro-fin tubes with outer diameter of 9.52 mm were used as test sections, and it was uniformly heated by applying direct current to the test tubes. Experiments were conducted at mass flow rates of 20 and 30 kg/hr. For each mass flow rate condition, evaporation temperature was set at 5 and $15^{\circ}C$and heat flux was changed from 6 to 11 kW/$m^2$ The evaporative heat transfer coefficient of micro-fin tubes after expansion is decreased because of the crush of fins and enlargement of inner diameter compared to that before expansion. Convective boiling effect decreased remarkably at higher quality range in the micro-fin tube after expansion, and the difference of the heat transfer coefficient in micro-fin tubes before and after expansion was greater for higher quality region. The evaporative heat transfer coefficient of the micro-fin tube after expansion was 19.9% smaller on the average than that before expansion.

• Journal of Environmental Science International
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• v.23 no.10
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• pp.1763-1773
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• 2014

It is known that mackerel and pork belly release a strong odor in the process of roasting. We evaluated a dilution factor of odor arising during roasting mackerel or pork belly and the relative odor strength using several cooking tools and analyzed compounds causing odors with gas chromatograph/mass detector. Roasting pans used were grill with lid, electric grill without lid and general roasting pan, and a grill with lid can attach the activated carbon charcoal deodorant at the inside of lid. And all electric grills have a drip tray under the heater. We investigated characteristics of odor emission depending on the presence of water and deodorants in these cooking tools. Study has shown that roasting mackerel produces approximately 36 time more odors than roasting pork belly, and the reduced odor emission when roast with water. And it shows the reduced deodorant effect when cooked with water after attaching activated carbon charcoal in the cooking pan. Major odor causing compounds arising when cooking mackerel and pork belly were aldehydes with high boiling point such as octyl aldehyde with a low odor threshold value.

• Journal of Technologic Dentistry
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• v.23 no.1
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• pp.75-83
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• 2001

This study was conducted to find antibacterial agent against growth of dental caries bacteria. St. mutans KDJ-50 from various medicinal plants of which safety was indetified. Medicinal plants used in this study was dried and grinded after purchased at Daegu yakryung sijang and Kyungsan jungang sijang. Medicinal plants extracted with 80% ethanol at boiling point for 3 hrs was used as antibacterial agent after freeze dried. This study was conducted to find antibacterial agent against growth of dental caries bacteria. St. mutans KDJ-50 from 32 medicinal plants of which safety was indetified. The result of using paper disc method. Caryophylli Flos. Coptidis Rhizoma. Phellodendri Cortex. Schizamdrae Fructs. Myristicae Semen, Crataegi Fructus and Acori Graminei Rhizoma was selected as antibacterial agent. The result of viable cell counting method. the antibacterial activity of Caryophylli Flos was highest among tested 7 medicinal plants followed by Phellodendri Cortex and Coptidis Rhizoma. The extinction effect of the St. mutans by Caryophylli Flos was shown with the addition of 0.5 (w/v) in the medium. The high antibacterial activity was acquired at high extraction temperature and long extraction temperature. The antibacterial activity of Caryophylli Flos was not effected by the concentration of ethanol.

• Journal of the Korean Ceramic Society
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• v.34 no.7
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• pp.767-773
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• 1997

Thermal shock behavior of alumina ceramics were studied by quenching the heated alumina specimen into the water of various temperatures over 0~10$0^{\circ}C$. The critical thermal shock temperature difference ( Tc) of the specimen decreased almost linearly from 275$^{\circ}C$ to 20$0^{\circ}C$ with increase in the cooling water temperature over 0~6$0^{\circ}C$. It is probably due to the increase of the maximum cooling rate which is dependent of the convection heat transfer coefficient. The convection heat transfer coefficient is a function of the temperature of the cooling water. However, the critical thermal shock temperature difference( Tc) of the specimen increased at 25$0^{\circ}C$ over 80~10$0^{\circ}C$ due to the film boiling of the cooling water. The maximum cooling rate, which brings about the maximum thermal stress of the specimen in the cooling process, was observed to increase linearly with the increase in the quenching temperature difference of the specimen due to the linear relationship of the convection heat transfer coefficient with the water temperature over 0~6$0^{\circ}C$. The critical maximum cooling rate for thermal shock fracture was observed almost constant to be about 260$\pm$1$0^{\circ}C$/s for all water temperatures over 0~6$0^{\circ}C$. Therefore, thermal shock behavior of alumina ceramics is greatly influenced by the convection heat transfer coefficient of the cooling water.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.660-670
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• 2009

Neighboring construction becomes mainstream of Ground excavation in downtown area. This causes the displacement, deformation, stress condition, etc of the ground surroundings. Therefore Neighboring construction have an effect on Neighboring structure. All these years a lot of Neighboring construction carried out, and the accumulation of technology also get accomplished. But earth retaining structure collapse happens yet. Types of earth retaining structure collapse are 12. 1. Failure of anchor or strut system, 2. Insufficiency of penetration, 3. H-pile Failure on excessive bending moment, 4. Slope sliding failure, 5. Excessive settlement of the back, 6. Deflection of H-pile, 7. Joint failure of coupled H-pile, 8. Rock failure when H-pile penetration is rock mass, 9. Plane arrangement of support systems are mechanically weak, 10. Boiling, 11. Heaving, 12. Over excavation. But field collapses are difficult for classification according to the type, because collapse process are complex with various types. When we consider the 12 collapse field, insufficient recognition of ground condition is 4 case. Thorough construction management prevents from fault construction. For limitations of soil survey, It is difficult to estimate ground condition exactly. Therefore, it should estimate the safety of earth retaining system, plan for necessary reinforcement, according to measurement and observation continuously.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.1
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• pp.17-27
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• 2009

Water jet impingement cooling is used to remove heat from high-temperature surfaces such as hot steel plates in the steel manufacturing process (thermo-mechanical cooling process; TMCP). In those processes, uniform cooling is the most critical factor to ensure high strength steel and good quality. In this study, experiments are performed to measure the heat transfer coefficient together with the inverse heat conduction problem (IHCP) analysis for a plate cooled by planar water jet. In the inverse heat transfer analysis, spatial and temporal variations of heat transfer coefficient, with no information regarding its functional form, are determined by employing the conjugate gradient method with an adjoint problem. To estimate the two dimensional distribution of heat transfer coefficient and heat flux for planar waterjet cooling, eight thermo-couple are installed inside the plate. The results show that heat transfer coefficient is approximately uniform in the span-wise direction in the early stage of cooling. In the later stage where the forced-convection effect is important, the heat transfer coefficient becomes larger in the edge region. The surface temperature vs. heat flux characteristics are also investigated for the entire boiling regimes. In addition, the heat transfer rate for the two different plate geometries are compared at the same Reynolds number.

• Nuclear Engineering and Technology
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• v.26 no.2
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• pp.237-246
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• 1994

A high flow critical heat flux (CHF) correlation, based on the single-pin CHF experimental data for finned and unfinned heated rods, was developed for the thermal-hydraulic design and safety analysis of the Korea Multi-purpose Research Reactor (KMRR) core. The correlation consists of dimensionless parameters such as Reynolds number, thermodynamic equilibrium quality, liquid-to-vapor density ratio, and hydraulic equivalent diameter ratio. The fin effect was taken into account in the correlation by a finned-to-unfinned heated perimeter ratio. The effects of a cold wall and non-uniform axial power distribution ore discussed to verify the applicability of the single-pin based correlation to the KMRR fuel bundle. The correlation limit departure from nucleate boiling ratio (DNBR) was determined as 1.44 from the statistical analysis of the CHF data.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.663-667
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• 2017

Delayed hydride cracking (DHC) was first observed in pressure tubes in Canadian CANDU reactors. In light water reactors, DHC was not observed until the late 1990s in high-burnup boiling water reactor (BWR) fuel cladding. In recent years, the focus on DHC has resurfaced in light of the increased interest in the cladding integrity during interim conditions. In principle, all spent fuel in the wet pools has sufficient hydrogen content for DHC to operate below $300^{\circ}C$. It is therefore of importance to establish the critical parameters for DHC to operate. This work studies the threshold stress intensity factor ($K_{IH}$) to initiate DHC as a function of temperature in Zry-4 for temperatures between $227^{\circ}C$ and $315^{\circ}C$. The experimental technique used in this study was the pin-loading testing technique. To determine the $K_{IH}$, an unloading method was used where the load was successively reduced in a stepwise manner until no cracking was observed during 24 hours. The results showed that there was moderate temperature behavior at lower temperatures. Around $300^{\circ}C$, there was a sharp increase in $K_{IH}$ indicating the upper temperature limit for DHC. The value for $K_{IH}$ at $227^{\circ}C$ was determined to be $2.6{\pm}0.3MPa$ ${\surd}$m.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.508-516
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• 1989

The objective of this study is to investigate on the pulsating combustion of a granular coal in a Rijke type pulse combustor. The combustor is made of a 120cm long pipe with a honeycomb as a fire grate in the lower half. A fixed amount of coal is laid on the honeycomb and burned downward after ignition by using propane gas. Then the combustion driven acoustic oscillation occurs and makes the combustion pulsate with a very high amplitude. The effect of the pulsation and the air flow rate on the combustion characteristics is examined in comparison with the normal combustion. The non-pulsating combustion is made possible by placing absorbing material under the honeycomb. The combustion phenomena are observed visually, the burning time is measured in order to evaluate the combustion rate, and the variation of the gas temperatures is recorded. It is found that the fuel particle is greatly agitated like boiling by the flow pulsation and the burning-down velocity is so fast that the fuel is burned almost simultaneously. The combustion rate can be increased as twice as that of non-pulsating combustion with increase of the air flow rate. And the combustion becomes clean with less soot deposit and emission.